FieLd Of View Visualizer


Welcome to FLOW Project !
FLOW is a visualization tool for SPICE users.

What's FLOW

"FLOW" is a Field Of View (FOV) visualizer for SPICE users, which creates an FOV image in JPEG/PNG/FITS formats using SPICE kernels. "FLOW" has the following features:

  • Draw planetary bodies (texture images or wire frame)
  • Draw planetary rings
  • Draw shape models (format: STL or SPICE DSK Type 2)
  • Draw stars
  • Support polygonal FOV
  • Support push broom scanner
  • Insert WCS keywords into FITS header
"FLOW" is composed of two console applications: simulation engine "flow_se" and image generator "flow_ig". "flow_se" reads observing condition from a configuration file (flow.conf) and calculates FOV using SPICE kernels. An XML file is created as a result of the calculation. "flow_ig" loads the XML output and texture images to create an FOV image (see below).


"FLOW" requires POSIX-compliant operating system (UNIX, Linux, BSD, etc.), and the necessary libraries are properly installed to build it.


  • CSPICE (N0066 or later)
  • libxml2 (2.7.6 or later)
  • lua (5.1.4 or later)
  • CFITSIO (v3.310 or later) (optional)
  • libpng (1.2.49 or later) (optional)
  • jpeglib (6 or later) (optional)

At least one of the CFITSIO, libpng, and jpeglib must be installed to generate an image. The format of planetary textures also depends on these libraries.

important "FLOW" users MUST know which SPICE kernels are essential to calculate FOV.


"FLOW" uses autoconf to create a build environment.
$ tar zxvf flow-1.4.tar.gz
$ cd flow-1.4
$ configure --with-cspice=/path/to/cspice
$ make
$ su
# make install

--with-cspice option is essential to address the path of cspice directory.

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Quick Start

The basic use is in below:
  1. Plan your simulation
  2. Download SPICE kernels you need
  3. Prepare planetary textures/shape models
  4. Create your configuration file (flow.conf)
  5. Execute the following commands:
$ flow_se -o mysim.xml flow.conf
$ flow_ig -o mysim.png mysim.xml
Or, use pipe instead:
$ flow_se flow.conf | flow_ig -o mysim.png
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Configuration File

The configuration file includes paths of SPICE kernels, textures, and models. In addition, there are observing conditions in it such as observing time and instruments. The "FLOW"'s configuration file is a Lua configuration file.

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"flow_se" Options

"flow_se" is a simulation engine. Inputting the configuration file as argument, "flow_se" outputs an XML file for rendering image. "flow_se" has some options. It is as follow: [-h][-t <time>][-o<outfile>][<infile>]


"flow_ig" Options

"flow_ig" is the image generator. It derive rendering image from the XML file which "flow_se" outputs. "flow_ig" have some options. It is as follows: [-h][-f][-m][-v][-s<scale>][-t<format>][-x<opts>...][-o<outfile>][<infile>]


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Experimental RPM package for Redhat 6.x (x86_64): Experimental Windows binary (i386): Experimental dmg image for Mac OS X (i386/x86_64):

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  • 1.Texture Format
  • 2.Coodinate System of The Model
  • 3.Related Files

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license and policy

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